An electrowetting display is an image display system which includes a substrate and, disposed thereon, a plurality of pixels filled with two phases of an aqueous medium and an oil-based coloring ink, and in which the affinity of the aqueous medium/substrate interface is controlled for each pixel by means of a voltage application on-off operation to spread/gather the oil-based coloring ink on the substrate and thereby an image is displayed (Non-Patent Document 1). The colorants for use in electrowetting displays are required to have high solubility in low-polarity solvents and the other properties (Patent Document 1 and Patent Document 2).
Patent Documents 3 to 6 show polyester fiber dye colorants each using a disazo compound excellent in fastness. Moreover, Patent Document 7 shows a cyan colorant for use in thermal-transfer sheets, which easily at least sublimes or thermally diffuses and an ink composition using the colorant, and mentions media for ink preparation.